Giant magnetoresistive sensor having horizontal stabilizer

ABSTRACT

A giant magnetoresistive (GMR) sensor for reading information from a magnetic storage medium has a first non-magnetoresistive layer, a first magnetoresistive layer formed on the first non-magnetoresistive layer, a second non-magnetoresitive layer formed on the first magnetoresistive layer, a second magnetoresistive layer formed on the second non-magnetoresistive layer, and a third non-magnetoresistive layer formed on the second magnetoresistive layer. The first non-magnetoresistive layer is provided with a single step on a surface of the first non-magnetoresistive layer. The step has an edge extending in a direction substantially parallel to a plane of a working surface of the GMR sensor.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.13/170,625 filed on Jun. 28, 2011, the disclosure of which isincorporated in its entirety by reference herein.

TECHNICAL FIELD

The following relates to a giant magnetoresistive (GMR) sensor having ahorizontal stabilizer provided therein.

BACKGROUND

Giant magnetoresistive (GMR) sensors used as read elements in magneticdata storage and retrieval systems need to operate in a linear andstable fashion. Especially when used as read elements in a multi-trackread/write head in magnetic tape data storage and retrieval systems, GMRsensors also need to operate as close to equivalent to each other aspossible.

GMR sensors, however, are unfortunately prone to defects which can causeinstability and bias point changes during their operation in such datastorage and retrieval systems. As a result, there exists a need for aGMR sensor that overcomes such problems. Such a GMR sensor wouldminimize the effects of such defects, thereby improving manufacturingyield and allowing the sensor to operate in a more stable fashion whenused in data storage and retrieval systems.

More specifically, such a sensor would be built incorporatingtopographic features that provide equivalent magnetic fields largeenough to minimize the effect of random manufacturing variations,thereby providing greater sensor equivalency in multi-track read/writeheads. Such topographical features would comprise a step in a layerbeneath the working surface of the GMR sensor. Such a step would beparallel to the working surface of the GMR sensor, such as the tapebearing surface of a GMR sensor in a magnetic tape data storage andretrieval system. Such a feature would provide for a GMR sensor whichallows multi-track GMR heads to be built with better yield, betterperformance, and less sensor variation between tracks.

SUMMARY

According to one embodiment disclosed herein, a giant magnetoresistive(GMR) sensor for reading information from a magnetic storage medium isprovided. The GMR sensor has a working surface oriented proximate themagnetic storage medium during operation of the GMR sensor. The GMRsensor comprises a first non-magnetoresistive layer, a firstmagnetoresistive layer formed on the first non-magnetoresistive layer, asecond non-magnetoresitive layer formed on the first magnetoresistivelayer, a second magnetoresistive layer formed on the secondnon-magnetoresistive layer, and a third non-magnetoresistive layerformed on the second magnetoresistive layer. The firstnon-magnetoresistive layer is provided with a single step on a surfaceof the first non-magnetoresistive layer, the step having an edgeextending in a direction substantially parallel to a plane of theworking surface of the GMR sensor.

According to another embodiment, a giant magnetoresistive (GMR) sensoris provided for reading information from a magnetic storage medium, theGMR sensor having a working surface oriented proximate the magneticstorage medium during operation of the GMR sensor. The GMR sensorcomprises a plurality of sensor stack layers comprising a plurality ofnon-magnetoresistive layers, and a plurality of magnetoresistive layersinterposed between the plurality of non-magnetoresistive layers. Each ofthe plurality of sensor stack layers is provided with a single step on asurface thereof, each step provided on the surface of each layer beingsubstantially coextensive with the step provided on the surface of anadjacent layer. Each step has an edge extending in a directionsubstantially parallel to a plane of the working surface of the GMRsensor.

According to a further embodiment, a method for manufacturing a giantmagnetoresistive (GMR) sensor for reading information from a magneticstorage medium is provided. The GMR sensor has a working surfaceoriented proximate the magnetic storage medium during operation of theGMR sensor. The method comprises forming a first non-magnetoresistivelayer, forming a first magnetoresistive layer on the firstnon-magnetoresistive layer, and forming a second non-magnetoresitivelayer on the first magnetoresistive layer. The method further comprisesforming a second magnetoresistive layer on the secondnon-magnetoresistive layer, and forming a third non-magnetoresistivelayer on the second magnetoresistive layer. The method still furthercomprises providing the first non-magnetoresistive layer with a singlestep on a surface of the first non-magnetoresistive layer, the stephaving an edge extending in a direction substantially parallel to aplane of the working surface of the GMR sensor.

A detailed description of these embodiments and accompanying drawings isset forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of material layers for use in a prior artanisotropic magnetoresistive (AMR) sensor;

FIG. 2 is a perspective view of exemplary material layers for use in agiant magnetoresistive (GMR) sensor;

FIG. 3 is a top view of a prior art AMR sensor with a stabilizer patternformed therein;

FIG. 4 is an edge-on view of the prior art AMR sensor depicted in FIG.3, taken along the line 4-4 thereof showing the stabilizer patternformed therein;

FIGS. 5, 5 b and 5 c are top views of an embodiment of the GMR sensordisclosed herein with a stabilizer pattern formed therein;

FIGS. 6, 6 b and 6 c are edge-on views of the embodiment of the GMRsensor disclosed herein and depicted in FIGS. 5, 5 b and 5 c, takenalong the lines 6-6, 6 b-6 b and 6 c-6 c thereof showing the stabilizerpattern formed therein;

FIG. 7 is an exemplary flowchart depicting an embodiment of a method formanufacturing a GMR sensor as disclosed herein;

FIG. 8 is a plot depicting amplitude output for multi-sensor GMR headshaving horizontal stabilizers as disclosed herein in comparison to aprior art multi-sensor GMR head without stabilization;

FIG. 9 is a plot depicting asymmetry for multi-sensor GMR heads havinghorizontal stabilizers as disclosed herein in comparison to a prior artmulti-sensor GMR head without stabilization;

FIG. 10 is a plot depicting stability for multi-sensor GMR heads havinghorizontal stabilizers as disclosed herein in comparison to a prior artmulti-sensor GMR head without stabilization;

FIG. 11 is a plot depicting Viterbi Quality Metric (VQM) for amulti-sensor GMR head having horizontal stabilizers as disclosed hereinin comparison to a prior art multi-sensor GMR head withoutstabilization; and

FIG. 12 is a plot of block error rate for a multi-sensor GMR head havinghorizontal stabilizers as disclosed herein in comparison to a prior artmulti-sensor GMR head without stabilization.

FIG. 13 is a perspective view of exemplary layers of the material layersfor use in a giant magnetoresistive (GMR) sensor shown in FIG. 2.

FIG. 14 is an exploded view of the exemplary layers of the materiallayers for use in a giant magnetoresistive (GMR) sensor shown in FIG.13.

DETAILED DESCRIPTION

With reference to FIGS. 1-12, a giant magnetoresistive (GMR) sensorhaving a horizontal stabilizer provided therein and a method formanufacturing such a GMR sensor will be described. For ease ofillustration and to facilitate understanding, like reference numeralsmay be used herein for like components and features throughout thedrawings.

As previously noted, GMR sensors used as read elements in magnetic datastorage and retrieval systems need to operate in a linear and stablefashion. Such GMR sensors also need to operate as close to equivalent toeach other as possible, especially when used as read elements in amulti-track read/write head in magnetic tape data storage and retrievalsystems.

GMR sensors, however, are prone to defects which can cause instabilityand bias point changes during their operation in such data storage andretrieval systems. The GMR sensor disclosed herein minimizes suchdefects, thereby improving manufacturing yield and allowing the GMRsensor to operate in a more stable fashion in data storage and retrievalsystems. The GMR sensor is built incorporating topographic featurescomprising a step in a layer beneath the working surface of the GMRsensor, such as the tape bearing surface of a GMR sensor in a magnetictape data storage and retrieval system, where the step is configuredparallel to the GMR sensor working surface (i.e., “horizontal”). Suchfeatures provide equivalent magnetic fields large enough to minimize theeffect of random manufacturing variations, thereby improving yield andproviding greater sensor equivalency in multi-track read/write heads.

Referring now to FIG. 1, a perspective view is shown of material layersfor use in a prior art anisotropic magnetoresistive (AMR) sensor. Asseen therein, an AMR sensor includes a non-magnetoresistive layer (14)and a magnetoresistive layer (16), which together may be referred to asa film stack (18). The non-magnetoresistive layer (14) may compriseCobalt-Zirconium-Tantalum (CoZrTa), while the magnetoresistive layer(16) may comprise Nickel-Iron (NeFe). As is well known in the art, suchan AMR sensor may be manufactured by creating or forming thenon-magnetoresistive and magnetoresistive layers (14, 16) using filmdeposition techniques. As is also well known, one side (20) of the filmstack (18) will be formed in a known fashion into a working surface forthe AMR sensor, which surface will be oriented proximate a magneticstorage medium (not shown) during operation of the AMR sensor. In a datastorage and retrieval system employing magnetic tape as the storagemedium, the working surface of the AMR sensor will be the tape bearingsurface where the AMR sensor makes contact with the magnetic tape (notshown).

A perspective view of exemplary material layers for use in a GMR sensoris shown in FIG. 2. As seen therein, a GMR sensor comprises a pluralityof non-magnetoresistive layers (14 a, 14 b, 14 c) and a plurality ofmagnetoresistive layers (16 a, 16 b, 16 c, 16 d). Here again, as is wellknown in the art, a GMR sensor may also be manufactured by creating orforming the non-magnetoresistive and magnetoresistive layers (14 a-c, 16a-d) using film deposition techniques. In that regard, the film stack(18′) of a GMR sensor may comprise a series of adjacent, alternating orinterposed non-magnetoresistive layers (14 a-c) and magnetoresistivelayers (16 a-d). As is also well known, one side (20′) of the film stack(18′) will be formed in a known fashion into a working surface for theGMR sensor, which surface will be oriented proximate a magnetic storagemedium (not shown) during operation of the GMR sensor. Here again, in adata storage and retrieval system employing magnetic tape as the storagemedium, the working surface of the GMR sensor will be the tape bearingsurface where the GMR sensor makes contact with the magnetic tape (notshown).

As seen in FIG. 2, one non-magnetoresistive layer (14 a) may compriseCopper (Cu), another non-magnetoresistive layer (14 b) may compriseRuthenium (Ru), and still another non-magnetoresistive layer (14 c) maycomprise Iridium-Manganese (IrMn). Magnetoresistive layers (16 a, 16 b)may comprise Nickel-Iron (NiFe) and Cobalt-Iron (CoFe), respectively.Additional magnetoresistive layers (16 c, 16 d) may comprise Cobalt-Iron(CoFe). It should be noted, however, that the particularmagnetoresistive and non-magnetoresistive materials identified hereinare exemplary only. Other magnetoresistive and non-magnetoresistivematerials may also be employed.

Referring next to FIG. 3, a top view of a prior art AMR sensor (22) isshown, including a stabilizer pattern (24) formed therein. The use oftopographical stabilizer techniques and features is well established inthe manufacture of AMR sensor read/write heads in order to improve AMRsensor performance when used in magnetic tape data storage and retrievalsystems. The salient features of such stabilizers are multiple stepheight changes beneath the working surface of the sensor.

More specifically, as seen in FIG. 3, a film stack (18) of AMR sensor(22) includes a magnetoresistive layer (16) oriented on top of anon-magnetoresistive layer (14). The film stack (18) will be provided ina known fashion with a working surface (26), which will be orientedproximate a magnetic storage medium (not shown) during operation of theAMR sensor (22). In a data storage and retrieval system where themagnetic storage medium is a magnetic tape, the working surface (26) ofthe AMR sensor (22) will be the tape bearing surface where the AMRsensor (22) makes contact with a magnetic tape (not shown).

Referring still to FIG. 3, the stabilizer pattern (24) provided in theAMR sensor (22) comprises multiple troughs (28) on the surface of thenon-magnetoresistive layer (14) adjacent the magnetoresistive layer(16). As can be seen, the troughs (28) are oriented at a 45° anglerelative to a plane formed by the working surface (26) of the AMR sensor(22).

FIG. 4 shows an edge-on view of the prior art AMR sensor (22) depictedin FIG. 3, taken along the line 4-4 thereof. In that regard, FIG. 4illustrates the stabilizer pattern (24) formed in the AMR sensor (22).As seen therein, multiple troughs (28) provided or formed in thenon-magnetoresistive layer (14) create a series of step height changeson surface (30) of the non-magnetoresistive layer (14) adjacentmagnetoresistive layer (16). In that regard, it should be noted that thetroughs (28) and concomitant surface step height changes may be formed,produced or provided in any known fashion, including chemical processessuch as photolithography, or mechanical processes such as machining orion milling.

Referring next to FIG. 5, a top view is shown of an embodiment of a GMRsensor (30) disclosed herein, including a stabilizer pattern (32) formedtherein. With reference again to FIGS. 1 and 2, GMR sensors differ fromAMR sensors in that GMR sensors are composed of a stack of multiple filmlayers, which are relatively thin in comparison to the material layersused in AMR sensors. In view of the relatively thin nature of the layersin a GMR sensor stack, it was thought that any step height changesprovided in those layers would damage the film integrity, therebyrendering the GMR sensor substantially inoperable. As a result, it wasbelieved that topographical stabilization features could not be used inGMR sensors.

Recent experiments with GMR sensors, however, have indicated thattopographical stabilizers can be quite successfully implemented. Indeed,stabilizers used in GMR sensors may be simpler than those used in AMRsensors in that only a single step, which may progress across the widthof the GMR sensor, may be provided. In that regard, as seen in FIGS. 5,5 b and 5 c, a portion of a film stack (18′) of GMR sensor (30) includesa magnetoresistive layer (16 c, 16 d) oriented on top of anon-magnetoresistive layer (14 a, 14 b), or a non-magnetoresistive layer(14 c) on top of a magnetoresistive layer (16 d). The film stack (18′)will be provided in a known fashion with a working surface (26′), whichwill be oriented proximate a magnetic storage medium (not shown) duringoperation of the GMR sensor (30). In a data storage and retrieval systemwhere the magnetic storage medium is a magnetic tape, the workingsurface (26′) of the GMR sensor (30) will be the tape bearing surfacewhere the GMR sensor (30) makes contact with a magnetic tape (notshown).

Still referring to FIGS. 5, 5 b and 5 c, the stabilizer pattern (32)provided in the GMR sensor (30) comprises a single step (34) on thesurface of the non-magnetoresistive layer (14 a, 14 b) adjacent themagnetoresistive layer (16 c. 16 d), or the non-magnetoresistive layer(14 c) adjacent the magnetoresistive layer (16 d). As can be seen, thestep (34) is oriented substantially parallel to a plane formed by theworking surface (26′) of the GMR sensor (30). In that regard, as it isoriented substantially parallel to the horizontal plane of the workingsurface (26′), the step (34) provides a topographical feature that maybe referred to as a horizontal stabilizer.

Referring now to FIGS. 6, 6 b and 6 c, edge-on views of the GMR sensor(30) depicted in FIGS. 5, 5 b and 5 c are shown, taken along the lines6-6, 6 b-6 b and 6 c-6 c thereof. In that regard, FIGS. 6, 6 b and 6 cillustrate the stabilizer pattern (32) formed in the GMR sensor (30). Asseen therein, the single step (34) provided or formed in thenon-magnetoresistive layer (14 a, 14 b) or the magnetoresistive layer(16 d) creates a step height change on surface (36) of thenon-magnetoresistive layer (14 a, 14 b) adjacent magnetoresistive layer(16 c, 16 d), or the magnetoresistive layer (16 d) adjacentnon-magnetoresistive layer (14 c), thereby forming a transitionalsurface (40) between first and second levels of the surface (36). Thestep (34) has an edge (38) that extends in a direction substantiallyparallel to a plane formed by the working surface (26′) (see, FIGS. 5, 5b and 5 c) of the GMR sensor (30), which may be a tape bearing surface.Once again, it should be noted that the step (34) and concomitantsurface height change may be formed, produced or provided in any knownfashion, including through the use of any chemical and/or mechanicalprocess.

With reference to FIGS. 5 and 6, as previously described, the step (34),including the edge (38) thereof, may extend across substantially theentire width of the GMR sensor (30). Moreover, while a step (34) isshown in one non-magnetoresistive layer (14 a), a similar step may beprovided on a surface of as many as all of the multiple magnetoresistiveand non-magnetoresistive layers in sensor stack (18′) that make up GMRsensor (30). In that regard, each such step may be substantiallycoextensive with the step provided in an adjacent layer, so that thesteps in each layer are substantially aligned in the sensor stack (18′)(see, FIG. 2) and/or extend across substantially the entire width of theGMR sensor (30).

Referring next to FIG. 7, an exemplary flowchart is shown of anembodiment of a method (60) for manufacturing a GMR sensor as disclosedherein. As previously described, the GMR sensor is for readinginformation from a magnetic storage medium, and has a working surfaceoriented proximate the magnetic storage medium during operation of theGMR sensor.

As seen in FIG. 7, the method (60) may comprise forming (62) a firstnon-magnetoresistive layer, forming (64) a first magnetoresistive layeron the first non-magnetoresistive layer, and forming (66) a secondnon-magnetoresitive layer on the first magnetoresistive layer. Themethod (60) may further comprise forming (68) a second magnetoresistivelayer on the second non-magnetoresistive layer; and forming (70) a thirdnon-magnetoresistive layer on the second magnetoresistive layer. Onceagain, such magnetoresistive and non-magnetoresistive layers maycomprise any of a number of materials, as discussed above in connectionwith FIGS. 1-6.

Still referring to FIG. 7, the method (60) for manufacturing a GMRsensor may further comprise providing (72) the firstnon-magnetoresistive layer with a single step on a surface of the firstnon-magnetoresistive layer, the step having an edge extending in adirection substantially parallel to a plane of the working surface ofthe GMR sensor. As previously discussed in connection with FIGS. 1-6,the magnetic storage medium may comprise a magnetic tape, the workingsurface of the GMR sensor may comprise a tape bearing surface, and theedge of the step provided on the surface of the firstnon-magnetoresistive layer thereby extends in a direction substantiallyparallel to a plane of the tape bearing surface of the GMR sensor.

The method (60) for manufacturing a GMR sensor may further compriseproviding the first magnetoresistive layer with a single step on asurface thereof, where the step provided on the surface of the firstmagnetoresistive layer is substantially coextensive with the stepprovided on the surface of the first non-magnetoresistive layer. Aspreviously discussed, the single step provided on the surface of thefirst non-magnetoresistive layer and the single step provided on thesurface of the first magnetoresistive layer may extend acrosssubstantially an entire width of the GMR sensor.

The method (60) may still further comprise providing each of the firstmagnetoresistive layer, the second non-magnetoresistive layer, thesecond magnetoresistive layer, and the third non-magnetoresistive layerwith a single step on a surface thereof, where each step provided on thesurface of each layer is substantially coextensive with the step provedon the surface of an adjacent layer. Here again, each of the coextensivesteps provided on the surface of each layer may extend acrosssubstantially an entire width of the GMR sensor. Moreover, as discussedabove in connection with FIGS. 1-6, the single step provided on thesurface of any of the magnetoresistive or non-magnetoresistive layersmay be produced by a chemical or a mechanical process. It should also benoted that while FIG. 7 shows the steps of the method (60) describedherein being executed in a particular order, that order is exemplaryonly. Such steps may be executed in a different order than thatdepicted, which may include simultaneous execution of particular steps.

Performance measurements of embodiments of GMR sensors as describedherein with horizontal stabilizers in comparison to GMR sensors lackingsuch features are shown in FIGS. 8-12. Referring first to FIG. 8, a plotdepicting amplitude output for multi-sensor GMR heads (80, 82) havinghorizontal stabilizers as disclosed herein is shown in comparison to aprior art multi-sensor GMR head (84) without stabilization. As seentherein, output on stabilized GMR heads (80, 82) is more tightlycontrolled than on non-stabilized GMR head (84). While the meanamplitude for stabilized GMR heads (80, 82) has dropped relative tonon-stabilized GMR head (84), that lower mean amplitude results from ofa lack of high output outliers for stabilized GMR heads (80, 82) ascompared to non-stabilized GMR head (84).

Referring next to FIG. 9, a plot depicting asymmetry for multi-sensorGMR heads (80, 82) having horizontal stabilizers as disclosed herein isshown in comparison to a prior art multi-sensor GMR head (84) withoutstabilization. As seen therein, asymmetry on stabilized GMR heads (80,82) is more tightly controlled that in non-stabilized GMR head (84). Thedistribution for stabilized GMR heads (80, 82) is more Gaussian than fornon-stabilized GMR head (84), without the large negative asymmetry tailof non-stabilized GMR head (84).

FIG. 10 is a plot depicting stability for multi-sensor GMR heads (80,82) having horizontal stabilizers as disclosed herein in comparison to aprior art multi-sensor GMR head (84) without stabilization. In thatregard, while stability measurements for GMR heads are better displayedas a cumulative distribution function, it is nevertheless easy todistinguish from FIG. 10 that stabilized GMR heads (80, 82) outperformnon-stabilized GMR head (84).

Referring now to FIG. 11, a plot depicting Viterbi Quality Metric (VQM)for a multi-sensor GMR head (80) having horizontal stabilizers asdisclosed herein is shown in comparison to a prior art multi-sensor GMRhead (84) without stabilization. As seen therein, magnetic tape drivetest results show that stabilized GMR head (80) has a higher VQM onaverage than non-stabilized GMR head (84), as well as a much reduced lowVQM tail.

FIG. 12 is a plot of block error rate (BLER) for a multi-sensor GMR headhaving horizontal stabilizers as disclosed herein in comparison to aprior art multi-sensor GMR head without stabilization. As seen therein,magnetic tape drive test results shown that stabilized GMR head (80) hasa good block error rate, and does not have the subset of sensors withpoorer error rates as does the non-stabilized GMR head (84).

As can be seen from the plots of FIGS. 8-12, multi-sensor GMR heads withhorizontal stabilizers improve parametric performance by producing atighter distribution of amplitude, producing a tighter distribution ofasymmetry, and reducing the incidence of unstable sensors to lowerlevels than multi-sensor GMR heads without stabilization. As well, interms of drive performance, stabilized GMR heads lead to a higher andbetter controlled VQM, lower the incidence of higher error rate sensors,and result in lower values of boost in the drive than non-stabilized GMRheads.

Referring now to FIGS. 13 and 14, perspective and exploded views areshown of exemplary layers of the material layers of the stack (18′)shown in FIG. 2. As seen therein, and with continuing reference to FIGS.2, 5 and 6, the stabilizer pattern (32) in the GMR sensor (30) comprisesa single step (34) on the surface (36) of the non-magnetoresistive layer(14 a) adjacent the magnetoresistive layer (16 c). The step (34) isoriented substantially parallel to a plane formed by the working surface(26′) of the GMR sensor (30), and therefore provides a topographicalfeature that may be referred to as a horizontal stabilizer. The singlestep (34) provided or formed in the non-magnetoresistive layer (14 a)creates a step height change on surface (36) of the non-magnetoresistivelayer (14 a) adjacent magnetoresistive layer (16 b). The step (34) hasan edge (38) that extends in a direction substantially parallel to aplane formed by the working surface (26′) of the GMR sensor (30), whichmay be a tape bearing surface. The step (34) thus provides atransitional surface (40) in the non-magnetoresistive layer (14 a)between first and second levels of the surface (36) of thenon-magnetoresistive layer (14 a) and has an edge (38) along a lineformed by a junction of the transitional surface (40) and the firstlevel of the surface (36) of the non-magnetoresistive layer (14 a),where the edge (38) extends in a direction substantially parallel to aplane formed by the working surface (26′) of the GMR sensor (30). Thestep (34), including the edge (38) thereof, may extend acrosssubstantially the entire width of the GMR sensor (30). While a step (34)is shown in one non-magnetoresistive layer (14 a), a similar step may beprovided on a surface of as many as all of the multiple mangetoresistiveand non-magnetoresistive layers in the sensor stack (18′) that make upGMR sensor (30). Each such step may be substantially coextensive withthe step provided in an adjacent layer, so that the steps in each layerare substantially aligned in the sensor stack (18′) and/or extend acrosssubstantially the entire width of the GMR sensor (30).

As is readily apparent from the foregoing description, a GMR sensor hasbeen disclosed that minimizes defects which can cause instability andbias point changes during sensor operation, thereby improvingmanufacturing yield and allowing the GMR sensor to operate in a morestable fashion when used in magnetic data storage and retrieval systems.The GMR sensor is built incorporating topographic features comprising astep in a layer beneath the working surface of the GMR sensor, such asthe tape bearing surface of a GMR sensor in a magnetic tape data storageand retrieval system, and is configured parallel to that GMR sensorworking surface (i.e., “horizontal”). Such features provide equivalentmagnetic fields large enough to minimize the effect of randommanufacturing variations, thereby providing greater sensor equivalencyin multi-track read/write heads. Such a GMR sensor allows multi-trackGMR heads to be built with better yield, better performance, and lesssensor-to-sensor variation.

While certain embodiments of a GMR sensor having a horizontal stabilizerhave been illustrated and described herein, they are exemplary only andit is not intended that these embodiments illustrate and describe allthose possible. Rather, the words used herein are words of descriptionrather than limitation, and it is understood that various changes may bemade without departing from the spirit and scope of the followingclaims.

What is claimed is:
 1. A method for manufacturing a giantmagnetoresistive (GMR) sensor for reading information from a magneticstorage medium, the GMR sensor having a working surface orientedproximate the magnetic storage medium during operation of the GMRsensor, the method comprising: forming a first non-magnetoresistivelayer; forming a first magnetoresistive layer on the firstnon-magnetoresistive layer; forming a second non-magnetoresitive layeron the first magnetoresistive layer; forming a second magnetoresistivelayer on the second non-magnetoresistive layer; providing the firstnon-magnetoresistive layer with only a single step on a surface thereof,the step providing a transitional surface in the firstnon-magnetoresistive layer between first and second levels of thesurface of the first non-magnetoresistive layer and having an edge alonga line formed by a junction of the transitional surface and the firstlevel of the surface of the first non-magnetoresistive layer, the edgeextending in a direction substantially parallel to a plane of theworking surface of the GMR sensor; and providing the firstmagnetoresistive layer with only a single step on a surface thereof, thestep provided on the surface of the first magnetoresistive layer beingsubstantially coextensive with the step provided on the surface of thefirst non-magnetoresistive layer; wherein the single step provided onthe surface of the first non-magnetoresistive layer and the single stepprovided on the surface of the first magnetoresistive layer each extendhorizontally across substantially an entire width of the GMR sensor. 2.The method of claim 1 wherein the magnetic storage medium comprises amagnetic tape, the working surface of the GMR sensor comprises a tapebearing surface, and the edge of the step provided on the surface of thefirst non-magnetoresistive layer extends in a direction substantiallyparallel to a plane of the tape bearing surface of the GMR sensor. 3.The method of claim 1 further comprising providing each of the the firstmagnetoresistive layer, the second non-magnetoresistive layer, and thesecond magnetoresistive layer with a single step on a surface thereof,each step provided on the surface of each layer being substantiallycoextensive with the step proved on the surface of an adjacent layer. 4.The method of claim 1 wherein the single step provided on the surface ofthe first non-magnetoresistive layer is produced by a chemical process.5. The method of claim 1 wherein the single step provided on the surfaceof the first non-magnetoresistive layer is produced by a mechanicalprocess.
 6. A method for manufacturing a giant magnetoresistive (GMR)sensor for reading information from a magnetic storage medium, the GMRsensor having a working surface oriented proximate the magnetic storagemedium during operation of the GMR sensor, the method comprising:forming a plurality of non-magnetoresistive layers; forming a pluralityof magnetoresistive layers interposed between the plurality ofnon-magnetoresistive layers; and providing each of the plurality oflayers with only a single step on a surface thereof, each step on thesurface of each layer being substantially coextensive with the stepprovided on the surface of an adjacent layer, each step providing atransitional surface in the associated layer between first and secondlevels of the surface of the associated layer and having an edge along aline formed by a junction of the transitional surface and the firstlevel of the surface of the associated layer, the edge extending in adirection substantially parallel to a plane of the working surface ofthe GMR sensor; wherein each step provided on the surface of each of theplurality of layers extends horizontally across substantially an entirewidth of the GMR sensor.
 7. The method of claim 6 wherein the magneticstorage medium comprises a magnetic tape, the working surface of the GMRsensor comprises a tape bearing surface.
 8. The method of claim 6wherein at least one of the steps provided on the surfaces of theplurality of layers is produced by a chemical process.
 9. The method ofclaim 6 wherein at least one of the steps provided on the surfaces ofthe plurality of layers is produced by a mechanical process.